Support unit for chair



July 15, 1969 L15 3,455,601

SUPPORT UNIT FOR CHAIR Filed Nov. 2, 1966 Sea Fran- United States Patent3,455,601 SUPPORT UNIT FOR CHAIR Finn Lie, Ring Mobelfabrikk A/ S,Moelv, Norway Filed Nov. 2, 1966, Ser. No. 591,566 Int. Cl. B6011 1/02;A47c 3/00 US. Cl. 297-301 3 Claims ABSTRACT OF THE DISCLOSURE A tiltingchair seat and/ or back support unit. A vertically disposed hollowtubular spring-containing sleeve is adapted for mounting upon a chairbase and carries forwardly projecting arms at its upper end. The seatand/or back are mounted upon the forward end of the arms for tiltingmovement about a horizontal axis and a link pivotally connects thesupported element to a plunger supported upon the sleeve containedspring, which acts in compression to resist rearward tilting of thesupported element.

It is an object of the present invention to provide a support frameassembly of compact construction which is readily adaptable for use in awide variety of tilting chair constructions.

It is another object of the invention to provide a support frame unit inaccordance with the foregoing object wherein a relatively small springelement may be employed to resiliently resist tilting movement over awide range of adjustments.

The foregoing, and other objects, are achieved in a support unit inwhich a support frame of relatively small size is provided with ahorizontal pivot adjacent its forward end and a vertically extendinghollow tubular sleeve adjacent its rearward end. A compression spring isenclosed in the sleeve and resiliently biases a plunger upwardly withinthe sleeve. The compression of the spring is readily adjusted by anadjustment screw bearing against the lower end of the spring. A supportlink is pivotally mounted upon the plunger and projects upwardly fromthe upper end of the sleeve. The upper end of the support link ispivotally connected to the tilting member of the chair which is alsoconnected to the pivot at the forward end of the frame element. Thebiasing action of the spring is thus applied to the tilting member ofthe chair at a point on the tilting member rearwardly of the axis aboutwhich the member tilts. By this arrangement, elevation of the front ofthe seat during tilting is minimized, the tilting motion is transmittedto the resisting spring by an extremely simple mechanism, and severalvariations or combinations of tilting seat-tilting back permutations canbe accomplished with substantially the same support frame unitconstruction. The tubular sleeve may be employed as the supporting shaftin swivel chair arrangements, if desired.

Other objects and features will become apparent by reference to thefollowing specification and to the drawmgs.

In the drawings:

FIGURE 1 is a detailed cross sectional view, taken on a central verticalplane, of one embodiment of the invention;

FIGURE 2 is a front elevational view of the structure of FIGURE 1;

FIGURE 3 is a partial side elevational view, with certain parts brokenaway or shown in broken line of a second embodiment of the invention;and

FIGURE 4 is a partial side elevational view similar to FIGURE 3, ofstill another form of the invention.

The basic support unit is shown in detail in FIGURES 1 and 2 asincluding a vertically extending hollow tubular 3,455,601 Patented July15, 1969 sleeve 1 having a frame element 2 fixedly secured, as bywelding, at its upper end. Frame element 2 is recessed as at 3 to fitover the top end of sleeve 1 and is formed with a slot-like aperture 4which provides clearance for a support link 14. Link 14 is pivotallycoupled at its lower end to a plunger 5 which is slidably mounted withinthe interior of sleeve 1, plunger 5 being slotted as at 15 to receivethe lower end of link 14, the lower pivot pin 5a being mounted in theplunger and passing laterally across the slot 15 through the lower endof link 14. A coil spring 7 is mounted within the interior of sleeve 1and engaged in compression between the underside of plunger 5 and asliding nut 6 within which is threadably received an adjustment screw 8.Adjustment screw 8 is formed with a flange 8a which rests on theinterior side of a plug member 9 fixedly mounted in the lower end ofsleeve 1. Screw 8 is freely rotatable within plug 1 and is provided witha knob 10 at its lower end for convenience in rotating the screw, tothereby run nut 6 axially up and down within sleeve 1 to vary thecompressive force of spring 7.

Because, in many installations, sleeve 1 is employed as the seatsupporting post where a chair seat is mounted for swivel movement upon abase, sleeve 1 is cylindrical. To prevent rotation of nut 6 within thesleeve, the opposite ends of spring 7 are seated within bores in plunger5 and nut 6 so that the torsional force of spring 7 resists rotation ofthe nut within the sleeve.

Frame element 2 is formed with a pair of forwardly projecting arms 11which, at their forward ends coopera-' tively support a pivot pin 12. Achair seat supporting frame 13 is pivotally supported upon pivot 12 andis also pivotally coupled, at a location rearwardly of pivot 12 to theupper end of support link 14 as by pivot pin 14a.

The basic unit of FIGURES l and 2 shows a structure which is adapted tosupport a chair seat indicated at S for pivotal movement about thehorizontal axis established by pivot pin 12. The support unit may, ifdesired, be supported upon a chair base A (FIGURE 3) so that sleeve 1acts as a vertical shaft upon which the chair seat may be swiveledrelative to the base A. Alternatively, the support unit may be fixedlymounted upon chair bases of various construction by suitable adaptorunits Whose structure will be adapted to the construction of theparticular base employed.

A modified form of the invention is shown in FIG- URE 3 in which theunit is employed to support a seat S in a stationary horizontal positionwhile accommodating rearward tilting movement of the chair back B. Partsin FIGURE 3 which correspond to parts in FIG- URE 1 have been identifiedby reference numerals which are primed. In the embodiment of FIGURE 3,the support frame element 2' is constructed with a modified form of sideportions 16 which are fixedly secured to the seat support link 13 whichacts as a platform upon which the chair seat S is fixedly mounted. Thechair back, partially indicated at B is mounted upon a back link havinga forwardly projecting link portion 17 which is pivotally mounted at itsforward end upon frame 2' by a pivot pin 18 which establishes thehorizontal axis about which the chair back B can tilt relative to thestationary elements of the support unit. As in the previous case, asupport link 14' is pivotally connected at its upper end by a pin 14a toback link 17 at a location spaced rearwardly from pivot 18. A supportsleeve 1 is fixedly secured to frame element 2' as in the previousembodiment and is provided with the same spring and adjusting mechanismas the embodiment of FIGURES 1 and 2 described above.

In FIGURE 4, there is disclosed another form of the invention in whichboth the chair seat and chair back are mounted for coordinated pivotalmovement relative to the fixed parts of the support unit. The frame 2"of the FIGURE 4 embodiment is formed with a slightly modified version ofside portion 16. A back link 17 of the same form as that of FIGURE 3 ispivotally supported upon the frame 2" by a pivot 18' and is pivotallycoupled to support link 14" as in the previous case. A modified form ofseat supporting link 13 is pivotally supported upon a pivot 19 at theextreme forward end of frame element 2 and a second support link 20 ispivotally coupled at one end to seat link 13" and to back link 17 bypivots 21 and 22 respectively.

The net result of the FIGURE 4 arrangement is a fourbar linkage whosefour corners are defined by the pivots 18, 19, 21 and 22 with thestationary link being located between pivots 18 and 19.

As in the previous cases a tubular sleeve 1" is fixed upon frame element2' and provided with the adjustable spring mechanism described in detailin connection with FIGURE 1. In the FIGURE 4 embodiment, the sameadjustable spring resiliently resists tilting movement of the seat andback of the chair, the tilting movement of the seat and back beingcoordinated and constrained by the four bar linkage mounted by pivots18', 19, 21 and 22.

While various embodiments of the invention have been described, it willbe apparent to those skilled in the art that the described embodimentsmay be modified. Therefore, the foregoing description is to beconsidered exemplary rather than limiting, and the true scope of theinvention is that defined in the following claims.

I claim:

1. In a chair having a base, and seat and back members; a support unitfor supporting at least one of said members upon said base for tiltingmovement about a horizontal axis comprising a support unit adapted to bemounted upon said base, a vertically disposed hollow tubular sleeveadapted to be mounted in said base, a frame element fixedly mounted uponthe upper end of said sleeve and having elongate arm means projectingforwardly from said sleeve, pivot means mounted upon the forward end ofsaid arm means for pivotally supporting said one of said members fortilting movement about a horizontal axis spaced forwardly of said chairfrom said tubular member, a plunger slidably mounted in the upper end ofsaid tubular sleeve, spring means mounted in said sleeve resilientlybiasing said plunger upwardly within said sleeve, a spring adjustmentscrew rotatably mounted in the lower end of said tubular member andprojecting axially downwardly therefrom, said screw having a knob on thelower end thereof, a nut threaded on said screw withinsaid tubularmember and engaged with the lower end of said spring, and a support linkpivotally connected at its lower end to said plunger and pivotallyconnected at its upper end to said one'of said members at a locationspaced rearwardly from said pivot means, said one of said members beingthe back member of said chair, the back member including a back linkprojecting forwardly from said back member and pivotally supported atits forward end upon said pivot means, said support link being pivotallyconnected at its upper end to said back link at a location spacedrearwardly on said back link from said pivot means.

2. The invention as defined in claim 1 wherein said seat member isfixedly mounted upon said support unit in spaced overlying relationshipto said back link.

3. The invention as defined in claim 1 further comprising a seat linkadapted to support the seat member of said chair, second pivot meanspivotally mounting said seat link upon said support unit adjacent theforward end of said support unit for pivotal movement about a secondhorizontal axis, and a second support link pivotally connected at oneend to said seat link at a location spaced rearwardly from said secondhorizontal axis and pivotally connected at its opposite end to said backlink at a location spaced rearwardly from said pivot means.

References Cited UNITED STATES PATENTS 2,689,599 9/1954 Mauser 297303 XR3,185,430 5/1965 Bernard 248381 3,220,687 11/1965 Baermann 2483783,284,133 11/1966 Werner 297-3 16 XR FOREIGN PATENTS 641,778 5 1962Canada.

FRANCIS K. ZUGEL, Primary Examiner US. Cl. X.R. 248-382

